Nintendo releases new downloads for Wii and DSi

This week's additions to the WiiWare and Nintendo DSiWare downloadable game services offer fast cars, talented canines and classic casino kicks. Gamers can get behind the wheel of a world-class speedster in Need for Speed: Nitro-X or enjoy short- and long-distance running challenges with Triple Running Sports. If it's pet-oriented fun you're after, Derby Dogs lets Wii owners raise their own talented pups and train them for competition, while Go Fetch! gives Nintendo DSi users a way to give their virtual pooches an active workout. For a taste of Las Vegas anywhere you go, 21: Blackjack puts a high-stakes card table in the palm of your hand.